Dual direct current external cardioversion in refractory atrial fibrillation: a systematic review and single-arm...

Electrical direct-current cardioversion (DCCV) is a cornerstone rhythm-control strategy for atrial fibrillation (AF). Conventional DCCV is less effective in patients with obesity and elevated transthoracic impedance, but the role of dual simultaneous DCCV in refractory AF remains uncertain.

We performed a systematic review and single-arm meta-analysis of dual simultaneous external DCCV, with quantitative synthesis restricted to adults with refractory AF after failed single-defibrillator cardioversion. PubMed, EMBASE, and the Cochrane Library were searched from inception through November 2025. The review followed PRISMA guidelines. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool and Newcastle-Ottawa Scale. Pooled estimates were calculated using a random-effects generalized linear mixed model, with Freeman-Tukey double-arcsine transformation for sensitivity analyses. Eight studies were included in the qualitative synthesis and seven in the meta-analysis. Pooled cardioversion success was 79% (95% CI, 74%-83%; I² = 0%). Ventricular arrhythmias occurred in 1% of patients (95% CI, 0%-4%) and transient bradyarrhythmia in 13% (95% CI, 4%-31%); no deaths were reported. Exploratory subgroup analyses showed no significant differences in success by pad configuration or number of prior failed single-defibrillator attempts.

Dual simultaneous external DCCV was associated with high acute conversion success and few reported serious adverse events in refractory AF. However, predominantly observational evidence, single-arm synthesis, heterogeneous procedural approaches, and limited contemporary biphasic data constrain conclusions regarding comparative efficacy, safety, and optimal patient selection. Prospective comparative studies using contemporary biphasic defibrillators are needed to define its clinical role, including evaluation in emergency department and other acute-care settings, before routine implementation.